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Patterson E, Powers M, Metcalfe PE, Cutajar D, Oborn BM, Baines JA. Electron streaming dose measurements and calculations on a 1.5 T MR-Linac. J Appl Clin Med Phys 2024:e14370. [PMID: 38661097 DOI: 10.1002/acm2.14370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 01/04/2024] [Accepted: 04/08/2024] [Indexed: 04/26/2024] Open
Abstract
PURPOSE To evaluate the accuracy of different dosimeters and the treatment planning system (TPS) for assessing the skin dose due to the electron streaming effect (ESE) on a 1.5 T magnetic resonance (MR)-linac. METHOD Skin dose due to the ESE on an MR-linac (Unity, Elekta) was investigated using a solid water phantom rotated 45° in the x-y plane (IEC61217) and centered at the isocenter. The phantom was irradiated with 1 × 1, 3 × 3, 5 × 5, 10 × 10, and 22 × 22 cm2 fields, gantry at 90°. Out-of-field doses (OFDs) deposited by electron streams generated at the entry and exit surface of the angled phantom were measured on the surface of solid water slabs placed ±20.0 cm from the isocenter along the x-direction. A high-resolution MOSkin™ detector served as a benchmark due to its shallower depth of measurement that matches the International Commission on Radiological Protection (ICRP) recommended depth for skin dose assessment (0.07 mm). MOSkin™ doses were compared to EBT3 film, OSLDs, a diamond detector, and the TPS where the experimental setup was modeled using two separate calculation parameters settings: a 0.1 cm dose grid with 0.2% statistical uncertainty (0.1 cm, 0.2%) and a 0.2 cm dose grid with 3.0% statistical uncertainty (0.2 cm, 3.0%). RESULTS OSLD, film, the 0.1 cm, 0.2%, and 0.2 cm, 3.0% TPS ESE doses, underestimated skin doses measured by the MOSkin™ by as much as -75.3%, -7.0%, -24.7%, and -41.9%, respectively. Film results were most similar to MOSkin™ skin dose measurements. CONCLUSIONS These results show that electron streams can deposit significant doses outside the primary field and that dosimeter choice and TPS calculation settings greatly influence the reported readings. Due to the steep dose gradient of the ESE, EBT3 film remains the choice for accurate skin dose assessment in this challenging environment.
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Affiliation(s)
- Elizabeth Patterson
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
| | - Marcus Powers
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Townsville Cancer Centre, Townsville Hospital and Health Service, Townsville, Queensland, Australia
| | - Peter E Metcalfe
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
- Illawarra Health Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
| | - Dean Cutajar
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
- Department of Radiation Oncology, St George Cancer Care Centre, Wollongong, New South Wales, Australia
| | - Bradley M Oborn
- Centre for Medical and Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia
- Institute of Radiooncology- OncoRay, Helmholtz-Zentrum Dresden-Rossendorf, Radiooncology, Dresden, Germany
- Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, New South Wales, Australia
| | - John A Baines
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Townsville Cancer Centre, Townsville Hospital and Health Service, Townsville, Queensland, Australia
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Wang D, Polignani JA. Quantitative approaches in electron skin collimation for the practical benefits. J Appl Clin Med Phys 2024; 25:e14236. [PMID: 38050939 PMCID: PMC11005976 DOI: 10.1002/acm2.14236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/07/2023] Open
Affiliation(s)
- Dongxu Wang
- Department of Medical PhysicsMemorial Sloan Kettering Cancer CenterNew YorkNew YorkUSA
| | - Jonathan A. Polignani
- Department of Medical PhysicsMemorial Sloan Kettering Cancer CenterNew YorkNew YorkUSA
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Moutrie V, Walker A. Commissioning of a RayStation structure template for the iBEAM evo Couchtop. Phys Eng Sci Med 2023; 46:1803-1809. [PMID: 37615922 DOI: 10.1007/s13246-023-01311-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/25/2023] [Indexed: 08/25/2023]
Abstract
Accurate radiotherapy treatment planning requires attenuation through the treatment couch to be accounted for in dose calculation. This is commonly performed by using contouring tools to add a virtual structure in the shape of the treatment couch and assigning the preferred absorption properties. The RayStation treatment planning system (TPS) allows users to assign a material that comprises both an elemental structure and a physical density. The selection of such parameters should be made so that modelled attenuation through the couch closely matches measured data. When these measurements involve the use of plastic phantoms and rotational beams, the validity of the data is dependent upon aspects of TPS and linear accelerator performance that can be difficult to quantify. A fundamental measure of couch attenuation using an ionisation chamber in water and perpendicular beam geometry that required no gantry movement was implemented to eliminate the identified uncertainties. This data was used to determine the combination of elemental composition and density assigned to a modelled couch structure that provided the most accurate representation of beam attenuation in this simple geometry. The preferred material was then validated using a cylindrical phantom and rotational beams. The findings were equivalent between the static gantry with water phantom and rotating gantry with cylindrical phantom. Of the elemental compositions investigated, it was possible to achieve suitable agreement with the measured data for each option provided the density was optimised. Choice of the elemental composition was not observed to be an important factor in achieving a good model.
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Affiliation(s)
- Vaughan Moutrie
- South Western Sydney Cancer Services, Sydney, Australia.
- Ingham Institute for Applied Medical Research, Sydney, Australia.
| | - Amy Walker
- South Western Sydney Cancer Services, Sydney, Australia
- Ingham Institute for Applied Medical Research, Sydney, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
- South West Sydney Clinical Campuses, University of New South Wales, Sydney, NSW, Australia
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Fagerstrom JM. Dosimetric characterization of foam padding with posterior fields in palliative radiation therapy. Med Dosim 2023; 49:65-68. [PMID: 37673727 DOI: 10.1016/j.meddos.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/12/2023] [Accepted: 08/09/2023] [Indexed: 09/08/2023]
Abstract
Patients undergoing external beam radiation therapy for the palliative treatment of painful bony metastases may have difficulty maintaining a still position on a rigid uncovered couch top, both during CT simulation as well as during patient setup, image guidance, and treatment on the linear accelerator. For these patients, a thin foam pad or mattress is sometimes used to mitigate patient discomfort. It was desired to quantify the effect of the padding in cases in which the patient is to be treated supine with posterior beams when the majority of the beam weighting traverses both the couch and the pad. Ion chamber measurements in-phantom were acquired with 6 MV, 10 MV, and 15 MV photon beams. At depths of maximum dose, the pad resulted in a difference of signal collected ≤1%. At the phantom surface, the pad resulted in an increase in signal ranging from 1% to 6.5% for the measured beams. CT data of the pad, both with and without applied pressure, indicated that the pad had average HU values close to air.
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Affiliation(s)
- Jessica M Fagerstrom
- Northwest Medical Physics Center, Lynnwood, WA, 98036; Kaiser Permanente, Seattle, WA, 98112.
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Kato T, Sasaki S, Ikeda T, Kato R, Kato M, Narita Y, Oyama S, Komori S, Harada T, Murakami M. Dosimetric effect of six degrees of freedom couch top with rotational setup error corrections in proton therapy. J Appl Clin Med Phys 2023; 24:e14043. [PMID: 37254641 PMCID: PMC10476984 DOI: 10.1002/acm2.14043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 02/25/2023] [Accepted: 05/02/2023] [Indexed: 06/01/2023] Open
Abstract
PURPOSE To investigate the dosimetric effect of six degrees of freedom (6DoF) couch top with rotational corrections in proton therapy (PT). METHODS The water equivalent thickness (WET) was measured using a proton beam with a 6DoF couch top and patient immobilization base plate (PIBP) placed in front of a motorized water phantom. The accuracy verification was performed with the beam axis set perpendicular to the 6DoF couch top and tilted in 10° steps from 10° to 30°. Up to 3° rotational correction may be added during the actual treatment to correct the rotational setup error on our system. The measured and calculated values using the treatment planning system were compared. Additionally, the effect of the 3° difference was evaluated using actual measurements concerning each angle on the proton beam range. RESULTS The WET of the 6DoF couch top and PIBP were 8.5 ± 0.1 mm and 6.8 ± 0.1 mm, respectively. The calculation and the actual measurement at each angle agreed within 0.2 mm at the maximum. A maximum difference of approximately 0.6 mm was confirmed when tilted at 3° following 30° with the 6DoF couch top plus PIBP. CONCLUSIONS The dosimetric effect of the 6DoF couch top with rotational corrections in PT differs depending on the incidence angle on the couch top, and it increased with the increased oblique angle of incidence. However, the effect on the range was as small as 0.6 mm at the maximum. The amount of rotational correction, the angle of incidence of the beam, and the effect of rotational corrections on the proton beam range may differ depending on the structure of the couch top. Therefore, sufficient prior confirmation, and subsequent periodical quality assurance management are important.
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Affiliation(s)
- Takahiro Kato
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Sho Sasaki
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Tomohiro Ikeda
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Ryohei Kato
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Masato Kato
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Yuki Narita
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Sho Oyama
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Shinya Komori
- Department of Radiation Physics and Technology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
| | - Takaomi Harada
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Masao Murakami
- Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, Fukushima, Japan
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Masitho S, Grigo J, Brandt T, Lambrecht U, Szkitsak J, Weiss A, Fietkau R, Putz F, Bert C. Synthetic CTs for MRI-only brain RT treatment: integration of immobilization systems. Strahlenther Onkol 2023; 199:739-748. [PMID: 37285037 PMCID: PMC10361877 DOI: 10.1007/s00066-023-02090-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 04/25/2023] [Indexed: 06/08/2023]
Abstract
PURPOSE Auxiliary devices such as immobilization systems should be considered in synthetic CT (sCT)-based treatment planning (TP) for MRI-only brain radiotherapy (RT). A method for auxiliary device definition in the sCT is introduced, and its dosimetric impact on the sCT-based TP is addressed. METHODS T1-VIBE DIXON was acquired in an RT setup. Ten datasets were retrospectively used for sCT generation. Silicone markers were used to determine the auxiliary devices' relative position. An auxiliary structure template (AST) was created in the TP system and placed manually on the MRI. Various RT mask characteristics were simulated in the sCT and investigated by recalculating the CT-based clinical plan on the sCT. The influence of auxiliary devices was investigated by creating static fields aimed at artificial planning target volumes (PTVs) in the CT and recalculated in the sCT. The dose covering 50% of the PTV (D50) deviation percentage between CT-based/recalculated plan (∆D50[%]) was evaluated. RESULTS Defining an optimal RT mask yielded a ∆D50[%] of 0.2 ± 1.03% for the PTV and between -1.6 ± 3.4% and 1.1 ± 2.0% for OARs. Evaluating each static field, the largest ∆D50[%] was delivered by AST positioning inaccuracy (max: 3.5 ± 2.4%), followed by the RT table (max: 3.6 ± 1.2%) and the RT mask (max: 3.0 ± 0.8% [anterior], 1.6 ± 0.4% [rest]). No correlation between ∆D50[%] and beam depth was found for the sum of opposing beams, except for (45° + 315°). CONCLUSION This study evaluated the integration of auxiliary devices and their dosimetric influence on sCT-based TP. The AST can be easily integrated into the sCT-based TP. Further, we found that the dosimetric impact was within an acceptable range for an MRI-only workflow.
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Affiliation(s)
- Siti Masitho
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany.
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany.
| | - Johanna Grigo
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Tobias Brandt
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Ulrike Lambrecht
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Juliane Szkitsak
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Alexander Weiss
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Rainer Fietkau
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Florian Putz
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Christoph Bert
- Department of Radiation Oncology, Strahlenklinik, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 27, 91054, Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
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Ehler ED. Clinical experience in the use of 3D printing as a rapid replacement of traditional radiation therapy immobilization materials. J Appl Clin Med Phys 2023:e14008. [PMID: 37128743 PMCID: PMC10402670 DOI: 10.1002/acm2.14008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/10/2023] [Accepted: 04/12/2023] [Indexed: 05/03/2023] Open
Abstract
PURPOSE Patient positioning and immobilization devices are commonly employed in radiation therapy. Unfortunately, cases can arise where the devices need to be reconstructed or improved. This work describes clinical processes to use a planning CT, to design and 3D print immobilization devices for reproducible patient positioning within a clinically feasible time frame when traditional methods can no longer be used or are insufficient. MATERIALS/METHODS Three clinical cases required rapid 3D printing of an immobilization device mid-treatment due to the following: (1) a lost headrest cushion, (2) needed improvement in lumbar spine positioning, and (3) a partially deflated vacuum immobilization mattress. RESULTS In the three cases, the 3D printed immobilization devices were clinically implemented successfully; two of the devices were fully designed and printed in 1 day. The 3D printed immobilization devices achieved a positioning accuracy sufficient to avoid the necessity to repeat the simulation and planning process. CONCLUSION If traditional immobilization devices fail or are misplaced, it is feasible to have a 3D printed replacement within the time span of 1 day. The design and fabrication methods, as well as the experiences gained, are described in detail to assist clinicians to implement 3D printing for similar situations.
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Affiliation(s)
- Eric D Ehler
- Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, USA
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Snyder KC, Mao W, Kim JP, Cunningham J, Chetty IJ, Siddiqui SM, Parikh P, Dolan J. Commissioning, clinical implementation, and initial experience with a new brain tumor treatment package on a low‐field MR‐linac. J Appl Clin Med Phys 2023. [DOI: 10.1002/acm2.13919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Affiliation(s)
- Karen Chin Snyder
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
| | - Weihua Mao
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
| | - Joshua P. Kim
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
| | | | - Indrin J. Chetty
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
| | - Salim M. Siddiqui
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
| | - Parag Parikh
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
| | - Jennifer Dolan
- Department of Radiation Oncology Henry Ford Health Detroit Michigan USA
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Jiang K, MacFarlane M, Mossahebi S, Zakhary MJ. Evaluation of treatment planning system accuracy in estimating the stopping-power ratio of immobilization devices for proton therapy. J Appl Clin Med Phys 2023; 24:e13831. [PMID: 36593751 PMCID: PMC9924110 DOI: 10.1002/acm2.13831] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 01/04/2023] Open
Abstract
PURPOSE To assess treatment planning system (TPS) accuracy in estimating the stopping-power ratio (SPR) of immobilization devices commonly used in proton therapy and to evaluate the dosimetric effect of SPR estimation error for a set of clinical treatment plans. METHODS Computed tomography scans of selected clinical immobilization devices were acquired. Then, the water-equivalent thickness (WET) and SPR values of these devices based on the scans were estimated in a commercial TPS. The reference SPR of each device was measured using a multilayer ion chamber (MLIC), and the differences between measured and TPS-estimated SPRs were calculated. These findings were utilized to calculate corrected dose distributions of 15 clinical proton plans for three treatment sites: extremity, abdomen, and head-and-neck. The original and corrected dose distributions were compared using a set of target and organs-at-risk (OARs) dose-volume histogram (DVH) parameters. RESULTS On average, the TPS-estimated SPR was 19.5% lower (range, -35.1% to 0.2%) than the MLIC-measured SPR. Due to the relatively low density of most immobilization devices used, the WET error was typically <1 mm, but up to 2.2 mm in certain devices. Overriding the SPR of the immobilization devices to the measured values did not result in significant changes in the DVH metrics of targets and most OARs. However, some critical OARs showed noticeable changes of up to 6.7% in maximum dose. CONCLUSIONS The TPS tends to underestimate the SPR of selected proton immobilization devices by an average of about 20%, but this does not induce major WET errors because of the low density of the devices. The dosimetric effect of this SPR error was negligible for most treatment sites, although the maximum dose of a few OARs exhibited noticeable variations.
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Affiliation(s)
- Kai Jiang
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Michael MacFarlane
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Sina Mossahebi
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Mark J. Zakhary
- Department of Radiation OncologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
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Kong F, Lu M, Dong J, Wang D, Shi J, Li Z. Effect of linear accelerator carbon fiber couch on radiotherapy dose. PLoS One 2022; 17:e0277332. [PMID: 36346802 PMCID: PMC9642885 DOI: 10.1371/journal.pone.0277332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
This study aimed to explore the effect of carbon fiber couch on radiotherapy dose attenuation and gamma pass rate in intensity-modulated radiotherapy (IMRT) plans. A phantom inserted with an ionization chamber was placed at different positions of the couch, and the dose was measured by the chamber. Under the same positioning, the phantom dose was calculated using the real and virtual couch images, and the difference in the planned dose of radiotherapy was compared. Ten clinical IMRT plans were selected as dose verification data, and the gamma pass rates were compared between couch addition and non-addition conditions. When the radiation field was near 110° and 250°, the measured value attenuation coefficient of the ionization chamber at the joint of the couch was up to 34%; the attenuation coefficient of the treatment couch from the actual couch image calculated using the treatment planning system (TPS) was up to 33%; the attenuation coefficient of the virtual couch calculated using the TPS was up to 4.0%. The gamma pass rate of the dose verification near gantry angles 110° and 250° was low, and that of the joint could be lower than 85% under the condition of 3%/3 mm. The gamma pass rates of the radiation field passing through the couch were all affected. The dose was affected by the radiation field passing through the couch, with the largest effect when passing through the joint part of the treatment couch, followed by that of the main couch plate and extension plate. When the irradiation field passed through the joint and near 110° and 250° of the main couch, the dose difference was large, making it unsuitable for treatment.
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Affiliation(s)
- Fantu Kong
- The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Meiting Lu
- The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jie Dong
- The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Donghui Wang
- The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Junyue Shi
- Foresea Life Insurance Guangzhou General Hospital, Guangzhou, China
- China Institute of Atomic Energy, Beijing, China
- * E-mail: (JS); (ZL)
| | - Zhenghuan Li
- The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- * E-mail: (JS); (ZL)
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Possibilities and challenges when using synthetic computed tomography in an adaptive carbon-ion treatment workflow. Z Med Phys 2022:S0939-3889(22)00064-2. [PMID: 35764469 DOI: 10.1016/j.zemedi.2022.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/29/2022] [Accepted: 05/29/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND PURPOSE Anatomical surveillance during ion-beam therapy is the basis for an effective tumor treatment and optimal organ at risk (OAR) sparing. Synthetic computed tomography (sCT) based on magnetic resonance imaging (MRI) can replace the X-ray based planning CT (X-rayCT) in photon radiotherapy and improve the workflow efficiency without additional imaging dose. The extension to carbon-ion radiotherapy is highly challenging; complex patient positioning, unique anatomical situations, distinct horizontal and vertical beam incidence directions, and limited training data are only few problems. This study gives insight into the possibilities and challenges of using sCTs in carbon-ion therapy. MATERIALS AND METHODS For head and neck patients immobilised with thermoplastic masks 30 clinically applied actively scanned carbon-ion treatment plans on 15 CTs comprising 60 beams were analyzed. Those treatment plans were re-calculated on MRI based sCTs which were created employing a 3D U-Net. Dose differences and carbon-ion spot displacements between sCT and X-rayCT were evaluated on a patient specific basis. RESULTS Spot displacement analysis showed a peak displacement by 0.2 cm caused by the immobilisation mask not measurable with the MRI. 95.7% of all spot displacements were located within 1 cm. For the clinical target volume (CTV) the median D50% agreed within -0.2% (-1.3 to 1.4%), while the median D0.01cc differed up to 4.2% (-1.3 to 25.3%) comparing the dose distribution on the X-rayCT and the sCT. OAR deviations depended strongly on the position and the dose gradient. For three patients no deterioration of the OAR parameters was observed. Other patients showed large deteriorations, e.g. for one patient D2% of the chiasm differed by 28.1%. CONCLUSION The usage of sCTs opens several new questions, concluding that we are not ready yet for an MR-only workflow in carbon-ion therapy, as envisaged in photon therapy. Although omitting the X-rayCT seems unfavourable in the case of carbon-ion therapy, an sCT could be advantageous for monitoring, re-planning, and adaptation.
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Duarte J, Loja MAR, Portal R, Vieira L. 3D Printing of Abdominal Immobilization Masks for Therapeutics: Dosimetric, Mechanical and Financial Analysis. Bioengineering (Basel) 2022; 9:bioengineering9020055. [PMID: 35200408 PMCID: PMC8869160 DOI: 10.3390/bioengineering9020055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 12/03/2022] Open
Abstract
Molding immobilization masks is a time-consuming process, strongly dependent on the healthcare professional, and potentially uncomfortable for the patient. Thus, an alternative sustainable automated production process is proposed for abdominal masks, using fused deposition modelling (FDM) 3D printing with polylactic acid (PLA). Radiological properties of PLA were evaluated by submitting a set of PLA plates to photon beam radiation, while estimations of their mechanical characteristics were assessed through numerical simulation. Based on the obtained results, the abdominal mask was 3D printed and process costs and times were analyzed. The plates revealed dose transmissions similar to the conventional mask at all energies, and mechanical deformation guarantees the required immobilization, with a 66% final cost reduction. PLA proved to be an excellent material for this purpose. Despite the increase in labour costs, a significant reduction in material costs is observed with the proposed process. However, the time results are not favorable, mainly due to the printing technique used in this study.
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Affiliation(s)
- Jessica Duarte
- ISEL—Instituto Superior de Engenharia de Lisboa, ESTeSL–Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1549-020 Lisboa, Portugal;
| | - Maria Amélia Ramos Loja
- CIMOSM-Centro de Investigação em Modelação e Otimização de Sistemas Multifuncionais, ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1549-020 Lisboa, Portugal; (M.A.R.L.); (R.P.)
- IDMEC, IST-Instituto Superior Técnico, 1049-001 Lisboa, Portugal
| | - Ricardo Portal
- CIMOSM-Centro de Investigação em Modelação e Otimização de Sistemas Multifuncionais, ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1549-020 Lisboa, Portugal; (M.A.R.L.); (R.P.)
| | - Lina Vieira
- CIMOSM-Centro de Investigação em Modelação e Otimização de Sistemas Multifuncionais, ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1549-020 Lisboa, Portugal; (M.A.R.L.); (R.P.)
- H&TRC—Health & Technology Research Center, ESTeSL-Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal
- Correspondence:
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Gayake U, Tike P, Bangare M, Raveendran V, Phurailatpam R, George K, Musne V, Dhore A. Quantitative comparison of dosimetric data between the indigenous baseplate and commercially available carbon fiber baseplate for 6 and 15 MV photon energy. J Med Phys 2022; 47:145-151. [PMID: 36212209 PMCID: PMC9542997 DOI: 10.4103/jmp.jmp_90_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 11/08/2022] Open
Abstract
Background: This study aims to design an indigenous baseplate (ID baseplate) that is economically viable and dosimetrically comparable for radiotherapy patient treatment. An ID baseplate was designed and manufactured using wood plastic composition materials that are readily available in the market and were compared dosimetrically with the commercially available carbon fiber baseplate (CF baseplate). Materials and Methods: Surface dose and beam attenuation properties of both the baseplates (ID and CF) were measured using a parallel plate chamber and compared with the dose calculated from the treatment planning system (TPS). Separate computer tomography images of both the baseplates were acquired by placing solid water phantoms. These images were used for surface dose calculation in the TPS and were validated with experimental measurements. Proper densities were assigned to the couch and baseplates to avoid uncertainties in dose calculations. All measurements were performed at field sizes 10 cm × 10 cm for 6 MV and 15 MV photon beams. Results: The percentage surface dose measured for the ID baseplate and CF baseplate was found to be matching for 6 MV beam (98.2% and 97%, respectively); however, for the 15 MV beam, the ID baseplate showed a higher surface dose of 98.6% compared to CF baseplate (87.4%). For the ID baseplate, the percentage difference in the surface dose between that TPS calculated value and the measured values were 1.6% and 1.4% for 6MV and 15MV, respectively. The ID baseplate showed higher beam attenuation than the CF baseplate by 2.2% for the 6MV beam and 3.4% for the 15MV beam when proper electron densities were not assigned. The difference between the TPS calculated dose and delivered dose was achieved within 3% after assigning proper electron density to the couch and baseplate. Conclusions: The ID baseplate has shown acceptable dosimetric results and can be an economically viable alternative to the commercially available CF baseplates. The manufacturing cost of the ID baseplate was ten times cheaper than the CF baseplate.
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Tang LL, Chen YP, Chen CB, Chen MY, Chen NY, Chen XZ, Du XJ, Fang WF, Feng M, Gao J, Han F, He X, Hu CS, Hu DS, Hu GY, Jiang H, Jiang W, Jin F, Lang JY, Li JG, Lin SJ, Liu X, Liu QF, Ma L, Mai HQ, Qin JY, Shen LF, Sun Y, Wang PG, Wang RS, Wang RZ, Wang XS, Wang Y, Wu H, Xia YF, Xiao SW, Yang KY, Yi JL, Zhu XD, Ma J. The Chinese Society of Clinical Oncology (CSCO) clinical guidelines for the diagnosis and treatment of nasopharyngeal carcinoma. Cancer Commun (Lond) 2021; 41:1195-1227. [PMID: 34699681 PMCID: PMC8626602 DOI: 10.1002/cac2.12218] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/24/2021] [Accepted: 09/08/2021] [Indexed: 02/05/2023] Open
Abstract
Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor originating in the nasopharynx and has a high incidence in Southeast Asia and North Africa. To develop these comprehensive guidelines for the diagnosis and management of NPC, the Chinese Society of Clinical Oncology (CSCO) arranged a multi‐disciplinary team comprising of experts from all sub‐specialties of NPC to write, discuss, and revise the guidelines. Based on the findings of evidence‐based medicine in China and abroad, domestic experts have iteratively developed these guidelines to provide proper management of NPC. Overall, the guidelines describe the screening, clinical and pathological diagnosis, staging and risk assessment, therapies, and follow‐up of NPC, which aim to improve the management of NPC.
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Affiliation(s)
- Ling-Long Tang
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Yu-Pei Chen
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Chuan-Ben Chen
- Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Department of Radiation Oncology, Teaching Hospital of Fujian Medical University Provincial Clinical College, Cancer Hospital of Fujian Medical University, Fuzhou, Fujian, 350014, P. R. China
| | - Ming-Yuan Chen
- Department of Nasopharyngeal Carcinoma, State Key Laboratory of Oncology in South China, Collaborative Innovation Centre for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, 510060, P. R. China
| | - Nian-Yong Chen
- Department of Radiation Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, P. R. China
| | - Xiao-Zhong Chen
- Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Cancer and Basic Medicine (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang, 310000, P. R. China
| | - Xiao-Jing Du
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Wen-Feng Fang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Medical Oncology Department, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, 510060, P. R. China
| | - Mei Feng
- Department of Radiation Oncology, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610041, P. R. China
| | - Jin Gao
- Department of Radiation Oncology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, Anhui, 230001, P. R. China
| | - Fei Han
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Xia He
- Department of Clinical Laboratory, Affiliated Cancer Hospital of Nanjing Medical University, Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, Nanjing, Jiangsu, 210000, P. R. China
| | - Chao-Su Hu
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, P. R. China
| | - De-Sheng Hu
- Department of Radiotherapy, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430079, P. R. China
| | - Guang-Yuan Hu
- Department of Oncology, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, 430030, P. R. China
| | - Hao Jiang
- Department of Radiation Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, 233004, P. R. China
| | - Wei Jiang
- Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, P. R. China
| | - Feng Jin
- Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, No. 6, Xuefu West Road, Xinpu New District, Zunyi, Guizhou, 563000, P. R. China
| | - Jin-Yi Lang
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610041, P. R. China
| | - Jin-Gao Li
- Department of Radiotherapy, Jiangxi Cancer Hospital, Nanchang, Jiangxi, 330029, P. R. China
| | - Shao-Jun Lin
- Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fujian Medical University Department of Radiation Oncology, Teaching Hospital of Fujian Medical University Provincial Clinical College, Cancer Hospital of Fujian Medical University, Fuzhou, Fujian, 350014, P. R. China
| | - Xu Liu
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Qiu-Fang Liu
- Department of Radiotherapy, Shaanxi Provincial Cancer Hospital Affiliated to Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi, 710000, P. R. China
| | - Lin Ma
- Department of Radiation Oncology, First Medical Center of Chinese PLA General Hospital, Beijing, 100000, P. R. China
| | - Hai-Qiang Mai
- Department of Nasopharyngeal Carcinoma, State Key Laboratory of Oncology in South China, Collaborative Innovation Centre for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, 510060, P. R. China
| | - Ji-Yong Qin
- Department of Radiation Oncology, Yunnan Cancer Hospital, The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650100, P. R. China
| | - Liang-Fang Shen
- Department of Radiation Oncology, Xiangya Hospital of Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, P. R. China
| | - Ying Sun
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Pei-Guo Wang
- Department of Radiotherapy, National Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060, P. R. China
| | - Ren-Sheng Wang
- Department of Radiation Oncology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 530000, P. R. China
| | - Ruo-Zheng Wang
- Department of Radiation Oncology, Key Laboratory of Oncology in Xinjiang Uyghur Autonomous Region, The Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830000, P. R. China
| | - Xiao-Shen Wang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, P. R. China
| | - Ying Wang
- Department of Radiation Oncology, Chongqing University Cancer Hospital & Chongqing Cancer Institute & Chongqing Cancer Hospital, Chongqing, 400000, P. R. China
| | - Hui Wu
- Department of Radiation Oncology, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, 450000, P. R. China
| | - Yun-Fei Xia
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
| | - Shao-Wen Xiao
- Department of Radiotherapy, Peking University School of Oncology, Beijing Cancer Hospital and Institute, Beijing, Haidian District, 100142, P. R. China
| | - Kun-Yu Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430022, P. R. China
| | - Jun-Lin Yi
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, P. R. China
| | - Xiao-Dong Zhu
- Department of Radiotherapy, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, 530000, P. R. China
| | - Jun Ma
- Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, Guangdong, 510060, P. R. China
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Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator. Sci Rep 2021; 11:13504. [PMID: 34188139 PMCID: PMC8242010 DOI: 10.1038/s41598-021-92836-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 06/14/2021] [Indexed: 11/19/2022] Open
Abstract
Recently, a diagnostic helical CT is integrated into a linear accelerator, called uRT-linac 506c, whose CT scanning dataset can be directly used to do simulation. This novel structure provides a possibility for online adaptive radiotherapy. For adaptive radiotherapy, the carbon fiber couch is an essential external device for supporting and positioning patients. And the effect on dose attenuation and distribution caused by a couch is inevitable and vital for precise treatment. In this research, the couch equipped with uRT-linac 506c was evaluated on the radiation dosimetry effect. The treatment couch equipped on the uRT-linac 506c accelerator was evaluated, and its effect on the attenuation, surface dose and dose buildup were measured for different phantom positions (offset = 0 cm, offset = + 10 cm and offset = − 10 cm, respectively) and different gantry angles. Since uRT-linac 506c is exclusively capable to provide diagnostic CT scanning data with real relative electron density (RED), this CT scanning data of the couch can be used directly in uRT-TPS to design plans. This scanned couch dataset was designated as the model A. The model B was a dummy structure of a treatment couch inserted with artificially preset RED. The dose calculation accuracy of these two models was compared using PB, CC, and MC on uRT-TPS. With the effect of carbon fiber couch, the surface dose was increased at least 97.94% for 25 × 25 cm2 field and 188.83% for 10 × 10 cm2 field, compared with those without. At different phantom positions (offset = 0, + 10, − 10 cm), the attenuation for 6 MV photon beam at gantry angle 180° were 4.4%, 4.4%, and 4.3%, respectively, and varied with changes of gantry angle. There do exists dose deviation between measurement and TPS calculation with the involvement of treatment couch, among the three algorithms, MC presented the least deviation, and the model A made less and steadier deviation than the model B, showing promising superiority. The attenuation, surface dose, and buildup effects of the carbon fiber couch in this study were measured similarly to most counterparts. The dose deviation calculated based on the couch dataset scanned by the diagnostic helical CT was smaller than those based on a dummy couch. This result suggests that an accelerator equipped with a diagnostic CT, which can help reduce the dose deviation of the carbon fiber couch, is a promising platform for online adaptive radiotherapy.
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The effect of carbon fibre treatment couch with and without immobilisation devices on radiotherapy dose calculation using three different planning algorithms and photon beam energies. JOURNAL OF RADIOTHERAPY IN PRACTICE 2021. [DOI: 10.1017/s1460396921000315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
Introduction:
The objective of radiotherapy immobilisation devices is to improve the reproducibility of patient positioning during treatment sessions. The inclusion of these devices in the treatment protocol may increase the skin dose. In practice, these devices are not systematically taken into account in the dose calculation.
Material and methods:
In this study, the dosimetric effects of the carbon fibre couch iBEAM Evo Extension 415, with and without three different immobilisation devices (a Klarity Breastboard R610-2ECF, a Bionix Butterfly Board and CIVCO Vac-Lok vacuum bag), were calculated and evaluated on the dose calculation for conformal three-dimensional radiation therapy. The measurements were carried out by comparing the measured dose with the one calculated for three different algorithms, FFT convolution, fast superposition and superposition algorithms, which are implemented in Xio treatment planning system (TPS).
Results:
Dosimetric tolerance levels have been respected for specific dose calculations, which do not include the fibre couch with or without immobilisation devices. Errors of up to 8% in the dose calculation were obtained for the beams passing through the fibre couch and the breast board base support region.
Conclusion:
According to the significant attenuation differences of the beam by the fibre couch and immobilisation devices, it was concluded that ignoring the device in the dose calculation can change patient’s skin and target doses. The fibre couch and immobilisation device should be included within external body contour to account for the TPS calculation algorithms dose attenuation.
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Lv R, Yang G, Huang Y, Wang Y. Dosimetric effects of supine immobilization devices on the skin in intensity-modulated radiation therapy for breast cancer: a retrospective study. BMC Cancer 2021; 21:384. [PMID: 33836670 PMCID: PMC8034111 DOI: 10.1186/s12885-021-08119-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/29/2021] [Indexed: 11/25/2022] Open
Abstract
Background The dose perturbation effect of immobilization devices is often overlooked in intensity-modulated radiation therapy (IMRT) for breast cancer (BC). This retrospective study assessed the dosimetric effects of supine immobilization devices on the skin using a commercial treatment planning system. Methods Forty women with BC were divided into four groups according to the type of primary surgery: groups A and B included patients with left and right BC, respectively, who received 50 Gy radiotherapy in 25 fractions after radical mastectomy, while groups C and D included patients with left and right BC, respectively, who received breast-conservation surgery (BCS) and 40.05 Gy in 15 fractions as well as a tumor bed simultaneous integrated boost to 45 Gy. A 0.2-cm thick skin contour and two sets of body contours were outlined for each patient. Dose calculations were conducted for the two sets of contours using the same plan. The dose differences were assessed by comparing the dose-volume histogram parameter results and by plan subtraction. Results The supine immobilization devices for BC resulted in significantly increased skin doses, which may ultimately lead to skin toxicity. The mean dose increased by approximately 0.5 and 0.45 Gy in groups A and B after radical mastectomy and by 2.7 and 3.25 Gy in groups C and D after BCS; in groups A–D, the percentages of total normal skin volume receiving equal to or greater than 5 Gy (V5) increased by 0.54, 1.15, 2.67, and 1.94%, respectively, while the V10 increased by 1.27, 1.83, 1.36, and 2.88%; the V20 by 0.85, 1.87, 2.76, and 4.86%; the V30 by 1.3, 1.24, 10.58, and 11.91%; and the V40 by 1.29, 0.65, 10, and 10.51%. The dose encompassing the planning target volume and other organs at risk, showed little distinction between IMRT plans without and with consideration of immobilization devices. Conclusions The supine immobilization devices significantly increased the dose to the skin, especially for patients with BCS. Thus, immobilization devices should be included in the external contour to account for dose attenuation and skin dose increment. Trial registration This study does not report on interventions in human health care.
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Affiliation(s)
- Ran Lv
- Second Affiliated Hospital of Fujian Medical University, NO 950, Donghai Street, Fengze District, Quanzhou, 362000, Fujian, China
| | - Guangyi Yang
- Second Affiliated Hospital of Fujian Medical University, NO 950, Donghai Street, Fengze District, Quanzhou, 362000, Fujian, China
| | - Yongzhi Huang
- Second Affiliated Hospital of Fujian Medical University, NO 950, Donghai Street, Fengze District, Quanzhou, 362000, Fujian, China
| | - Yanhong Wang
- Second Affiliated Hospital of Fujian Medical University, NO 950, Donghai Street, Fengze District, Quanzhou, 362000, Fujian, China.
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Loughery B, Chan D, Burmeister J, Dominello M. Development of an in vivo technique for dose verification at the prone breast board / skin interface. J Appl Clin Med Phys 2021; 22:202-206. [PMID: 33760370 PMCID: PMC8035550 DOI: 10.1002/acm2.13229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/18/2020] [Accepted: 02/06/2021] [Indexed: 11/11/2022] Open
Abstract
Due to the limited height of commercial prone breast boards, large or pendulous breasts may contact the base layer of the board during simulation and throughout the course of treatment. Our clinic has historically identified and marked this region of contact to ensure reproducible setup. However, this situation may result in unwanted hotspots where the breast rests atop the board due to electron scatter. In this study, we performed in-vivo dosimetric measurements to evaluate the surface dose in regions of contact with the immobilization device. The average dose and hotspot were identified and evaluated to determine whether plan modifications were necessary to avoid excess skin toxicity at the skin/breast board interface. The film method results were validated against a commissioned in vivo OSLD dosimetry system. Radiochromic film measurements agreed with OSLD readings (n = 18) overall within 1%, σ = 6.4%, with one deviation of >10%. Pertinent information for the physician includes the average, maximum, and minimum doses received at the film interface. Future readings will not require OSLD verification. Physicians now have access to additional spatial data to correlate skin toxicity with doses delivered at the skin/breast board interface. This new technique is now an established procedure at our clinic, and can inform future efforts to model enhanced methods to calculate the dosimetric effects from the prone breast board in the treatment planning system.
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Affiliation(s)
- Brian Loughery
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Dennis Chan
- Department of Radiation Oncology, Karmanos Cancer Institute, Detroit, MI, USA.,Department of Radiation Oncology, Stritch School of Medicine, Cardinal Bernardin Cancer Center, Loyola University Chicago, Maywood, IL, USA
| | - Jay Burmeister
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA.,Department of Radiation Oncology, Karmanos Cancer Institute, Detroit, MI, USA
| | - Michael Dominello
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA.,Department of Radiation Oncology, Karmanos Cancer Institute, Detroit, MI, USA
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Hou L, Zhang H, Sun X, Liu Q, Chen T, Liu Y, Jiang X, Yao S. Dosimetric Evaluation of the QFix kVue TM Calypso Couch Top. Technol Cancer Res Treat 2021; 20:15330338211011964. [PMID: 33910440 PMCID: PMC8107663 DOI: 10.1177/15330338211011964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/25/2021] [Accepted: 03/29/2021] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To evaluate the dosimetric accuracy of the default couch model of the QFix kVueTM Calypso couch top in the treatment planning system. METHODS With the gantry 180°, field size 20 × 20 cm, 6 MV, we measured the depth dose, off-axis dose, and dose plane of different depths in the phantom with the couch rails in and out, respectively. Isocenter doses at different angles were also obtained. The results were compared to the doses calculated using the default couch top model and the real scanned couch top model. Then we revised the default model according to the measured results. RESULTS With "Rails In," the depth dose, off-axis dose, and dose plane of the default couch top model had a big difference with the dose of the real scanned couch top model and the measured result. The dose of the real scanned couch top model was much closer to the measured result, but in the region of the rail edge, the difference was still significant. With "Rails Out," there was a minor difference between the measured result, the dose of the default couch top model and the real scanned couch top model. The difference between the measurement and the default couch top model became very small after being revised. CONCLUSIONS It is better to avoid the beam angle passing through the couch rails in treatment plans, or you should revise the parameter of the QFix kVueTM Calypso couch top model based on the measured results, and verify the treatment plan before clinical practice.
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Affiliation(s)
- Lingtong Hou
- Department of Radiation Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huiqin Zhang
- Department of Oncology, The Affiliated Lianyungang Hospital of Xuzhou Medical University, Lianyungang, China
| | - Xiaomei Sun
- Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, China
| | - Qianqian Liu
- Department of Radiation Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tingfeng Chen
- Department of Radiation Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yong Liu
- Department of Radiation Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaodong Jiang
- Department of Oncology, The Affiliated Lianyungang Hospital of Xuzhou Medical University, Lianyungang, China
| | - Shengyu Yao
- Department of Radiation Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Implementation of carbon fibre treatment couches in the XiO ® and Monaco ® Treatment Planning Systems. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2020. [DOI: 10.2478/pjmpe-2020-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract
Purpose: Carbon fibre treatment couches on linear accelerators provide a strong, rigid framework for patient support. Patient safety is a priority, therefore the dosimetric properties of treatment couches need to be accurately incorporated in treatment plans, to minimize differences between planned and delivered dose. This study aims to determine the attenuation effect of treatment couches for 3-D Conformal Radiotherapy (3-D CRT) and to validate the implementation thereof in the XiO and Monaco treatment planning systems (TPS).
Material and methods: Attenuation measurements were performed on the ELEKTA Connexion couches of the ELEKTA Precise and Synergy-Agility linear accelerators. Measurements were made at 10° intervals in RMI-457 Solid water (30 cm x 30 cm x 30 cm) using a PTW Farmer-type ionization chamber (TW30013) positioned at the accelerator’s isocentre. The percentage attenuation was calculated as the ratio of the electrometer readings for parallel-opposed fields. The Computed Tomography (CT) data sets of the set-ups were obtained on a Philips Big Bore 16-slice CT scanner and exported to the TPS. The individual couch structures were delineated and electron density (ED) values were assigned using the commissioned CT-to-ED curve. Test treatment plans were generated with 100MU per field at 10° gantry intervals.
Results: The percentage attenuation was determined to be within 2% and 3% for beams perpendicular to the couch surface for XiO and Monaco, respectively. The maximum attenuation was observed for oblique fields which was significantly higher than the manufacturer specified values. TPS validation showed an agreement to 1% for XiO and Monaco. At extreme oblique angles, both planning systems overestimated this effect up to a maximum of 4%.
Conclusions: Couch attenuation differs significantly with gantry angle and beam energy. As a result, the treatment couch models should be included in all treatment planning calculations.
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Bosse C, Narayanasamy G, Saenz D, Myers P, Kirby N, Rasmussen K, Mavroidis P, Papanikolaou N, Stathakis S. Dose Calculation Comparisons between Three Modern Treatment Planning Systems. J Med Phys 2020; 45:143-147. [PMID: 33487926 PMCID: PMC7810148 DOI: 10.4103/jmp.jmp_111_19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose: Monaco treatment planning system (TPS) version 5.1 uses a Monte-Carlo (MC)-based dose calculation engine. The aim of this study is to verify and compare the Monaco-based dose calculations with both Pinnacle3 collapsed cone convolution superposition (CCCS) and Eclipse anisotropic analytical algorithm (AAA) calculations. Materials and Methods: For this study, 18 previously treated lung and head-and-neck (HN) cancer patients were chosen to compare the dose calculations between Pinnacle, Monaco, and Eclipse. Plans were chosen from those that had been treated using the Elekta VersaHD or a Novalis Tx linac. All of the treated volumetric-modulated arc therapy plans used 6 MV or 10 MV photon beams. The original plans calculated with CCCS or AAA along with the recalculated ones using MC from the three TPS were exported into Velocity software for intercomparison. Results: To compare the dose calculations, Planning target volume (PTV) heterogeneity indexes and conformity indexes were calculated from the dose volume histograms (DVH) of all plans. While mean lung dose (MLD), lung V5 and V20 values were recorded for lung plans, the computed dose to parotids, brainstem, and mandible were documented for HN plans. In plan evaluation, percent differences of the above dosimetric values in Monaco computation were compared against each of the other TPS computations. Conclusion: It could be concluded through this research that there can be differences in the calculation of dose across different TPSs. Although relatively small, these differences could become apparent when compared using DVH. These differences most likely arise from the different dose calculation algorithms used in each TPS. Monaco employs the MC allowing it to have much more detailed calculations that result in it being seen as the most accurate and the gold standard.
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Affiliation(s)
- Courtney Bosse
- Radiation Oncology, Colorado Associates in Medical Physics, Colorado Springs, CO 80907, USA
| | - Ganesh Narayanasamy
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Daniel Saenz
- Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Pamela Myers
- Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Neil Kirby
- Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Karl Rasmussen
- Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Panayiotis Mavroidis
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC, USA
| | - Niko Papanikolaou
- Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Sotirios Stathakis
- Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
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22
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Asfia A, Deepak B, Novak JI, Rolfe B, Kron T. Infill selection for 3D printed radiotherapy immobilisation devices. Biomed Phys Eng Express 2020; 6. [DOI: 10.1088/2057-1976/abb981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/17/2020] [Indexed: 12/19/2022]
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23
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Han MC, Kim J, Hong CS, Chang KH, Han SC, Park K, Kim DW, Park MK, Noh YY, Kim JS. Assessment of dosimetric leaf gap correction factor in Mobius3D commissioning affected by couch top. Phys Eng Sci Med 2020; 43:1069-1075. [PMID: 32700205 DOI: 10.1007/s13246-020-00905-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/14/2020] [Indexed: 11/29/2022]
Abstract
This study assesses the dosimetric leaf gap (DLG) correction factor in Mobius3D commissioning affected by a couch top platform and calculates the optimal DLG value according to the point dose difference function. DLG optimizations were performed for 3 LINAC machines and a total of 30 patient volumetric modulated arc therapy plans (i.e., 10 plans per each LINAC). Point dose calculations were performed using an automatic dose calculation system in Mobius3D as well as Mobis3D calculation using a Mobius Verification Phantom (MVP)-based quality assurance plan with a carbon fiber couch top. Subsequently, the results were compared with measurement data. The averaged point dose measured for the MVP with a couch top decreased by approximately 2% relative to that without the couch top. The average of the optimal DLG factors increased by 1.153 mm due to the couch top effect for a dose decrease of 2% at the measured point. In the procedure of Mobius beam commissioning, users should adjust the DLG correction factor using a specific phantom (including MVP) with a couch top structure. If the DLG optimization were performed by using MVP automatic dose calculation system, the factor should be increased by approximately 1.2 mm per 2% dose difference considering user's couch top effect.
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Affiliation(s)
- Min Cheol Han
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Jihun Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Chae-Seon Hong
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Kyung Hwan Chang
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Su Chul Han
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Kwangwoo Park
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Dong Wook Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Myoung Kyu Park
- Department of Radiation Oncology, Yonsei Cancer Center, Seoul, South Korea
| | - Yu Yun Noh
- Department of Radiation Oncology, Yonsei Cancer Center, Seoul, South Korea
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
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24
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Judge A, Feuz C, Evans D, Courtier N. Evaluating Canadian Radiation Therapists and UK Therapeutic Radiographers' Experiences and Opinions of a Safety Strap to Secure Patients during Radiotherapy. J Med Imaging Radiat Sci 2020; 51:436-442. [PMID: 32680827 DOI: 10.1016/j.jmir.2020.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/15/2020] [Accepted: 05/21/2020] [Indexed: 11/27/2022]
Abstract
INTRODUCTION A serious patient safety incident at a cancer centre in Ontario, Canada, saw a patient fall from an elevated treatment couch. A regional investigation recommended the use of a securing safety strap. The authors evaluate the value of the strap through the experiences of the radiation therapists' who use it. A secondary aim is to explore the potential for using a securing safety strap with UK therapeutic radiographers. METHODS A two-stage design was guided by an evidence-based practice framework. Stage one used a questionnaire to capture treating radiation therapists' experiences and opinions of the strap at a single cancer centre. Quantitative data were analysed descriptively and free-text data via a content analysis. Stage two used semistructured interviews with thematic analysis to explore views of three UK therapeutic radiographers. RESULTS Twenty-five of approximately 130 eligible staff responded to the Canadian questionnaire. Of the respondents, 24% (n = 6) 'strongly disagreed', 28% (n = 7) 'agreed' and 48% (n = 12) 'neither agreed nor disagreed' that they would recommend the strap to other departments. Most of the respondents think strap use should be at the staffs' discretion, with patients with dementia/cognitive impairment ranked as the group benefiting most. Ninety-two percent (n = 23) of respondents confirmed that patients sometimes refuse the strap. Themes arising from stage two interviews are as follows: patient benefit (use for select patients only); patient safety versus control (restraint); and practical implementation issues. CONCLUSION The policy of universal use of the strap should be reviewed. Those who use it are equivocal about its value and feel it should be reserved for select patients at the treating professional's discretion. Full evaluation of the effectiveness and acceptability of the device for different patients may promote both staff enthusiasm towards the device and evidence-based practice. Adequate resources are required to evaluate implementation of such safety initiatives.
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Affiliation(s)
- Annabelle Judge
- Cardiff University School of Healthcare Sciences, Cardiff, UK
| | - Carina Feuz
- Princess Margaret Cancer Centre, University Avenue, Toronto, Ontario, Canada
| | - David Evans
- The School of Healthcare Sciences, Queen Margaret University, Edinburgh, UK
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25
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Miura H, Ozawa S, Doi Y, Nakao M, Kubo K, Kenjo M, Nagata Y. Effectiveness of robust optimization in volumetric modulated arc therapy using 6 and 10 MV flattening filter-free beam therapy planning for lung stereotactic body radiation therapy with a breath-hold technique. JOURNAL OF RADIATION RESEARCH 2020; 61:575-585. [PMID: 32367109 PMCID: PMC7336549 DOI: 10.1093/jrr/rraa026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/27/2020] [Indexed: 06/11/2023]
Abstract
We investigated the feasibility of a robust optimization with 6 MV X-ray (6X) and 10 MV X-ray (10X) flattening filter-free (FFF) beams in a volumetric modulated arc therapy (VMAT) plan for lung stereotactic body radiation therapy (SBRT) using a breath-holding technique. Ten lung cancer patients were selected. Four VMAT plans were generated for each patient; namely, an optimized plan based on the planning target volume (PTV) margin and a second plan based on a robust optimization of the internal target volume (ITV) with setup uncertainties, each for the 6X- and 10X-FFF beams. Both optimized plans were normalized by the percentage of the prescription dose covering 95% of the target volume (D95%) to the PTV (1050 cGy × 4 fractions). All optimized plans were evaluated using perturbed doses by specifying user-defined shifted values from the isocentre. The average perturbed D99% doses to the ITV, compared to the nominal plan, decreased by 369.1 (6X-FFF) and 301.0 cGy (10X-FFF) for the PTV-based optimized plan, and 346.0 (6X-FFF) and 271.6 cGy (10X-FFF) for the robust optimized plan, respectively. The standard deviation of the D99% dose to the ITV were 163.6 (6X-FFF) and 158.9 cGy (10X-FFF) for the PTV-based plan, and 138.9 (6X-FFF) and 128.5 cGy (10X-FFF) for the robust optimized plan, respectively. Robust optimized plans with 10X-FFF beams is a feasible method to achieve dose certainty for the ITV for lung SBRT using a breath-holding technique.
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Affiliation(s)
- Hideharu Miura
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Shuichi Ozawa
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Yoshiko Doi
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Minoru Nakao
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | | | - Masahiko Kenjo
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
| | - Yasushi Nagata
- Hiroshima High-Precision Radiotherapy Cancer Center
- Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University
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26
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Alterio D, D’Ippolito E, Vischioni B, Fossati P, Gandini S, Bonora M, Ronchi S, Vitolo V, Mastella E, Magro G, Franco P, Ricardi U, Krengli M, Ivaldi G, Ferrari A, Fanetti G, Comi S, Tagliabue M, Verri E, Ricotti R, Ciardo D, Jereczek-Fossa BA, Valvo F, Orecchia R. Mixed-beam approach in locally advanced nasopharyngeal carcinoma: IMRT followed by proton therapy boost versus IMRT-only. Evaluation of toxicity and efficacy. Acta Oncol 2020; 59:541-548. [PMID: 32090645 DOI: 10.1080/0284186x.2020.1730001] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Objective: To compare radiation-induced toxicity and dosimetry parameters in patients with locally advanced nasopharyngeal cancer (LANPC) treated with a mixed-beam (MB) approach (IMRT followed by proton therapy boost) with an historic cohort of patients treated with a full course of IMRT-only.Material and methods: Twenty-seven patients with LANPC treated with the MB approach were compared to a similar cohort of 17 patients treated with IMRT-only. The MB approach consisted in a first phase of IMRT up to 54-60 Gy followed by a second phase delivered with a proton therapy boost up to 70-74 Gy (RBE). The total dose for patients treated with IMRT-only was 69.96 Gy. Induction chemotherapy was administrated to 59 and 88% and concurrent chemoradiotherapy to 88 and 100% of the MB and IMRT-only patients, respectively. The worst toxicity occurring during the entire course of treatment (acute toxicity) and early-late toxicity were registered according to the Common Terminology Criteria Adverse Events V4.03.Results: The two cohorts were comparable. Patients treated with MB received a significantly higher median total dose to target volumes (p = .02). Acute grade 3 mucositis was found in 11 and 76% (p = .0002) of patients treated with MB and IMRT-only approach, respectively, while grade 2 xerostomia was found in 7 and 35% (p = .02) of patients treated with MB and IMRT-only, respectively. There was no statistical difference in late toxicity. Local progression-free survival (PFS) and progression-free survival curves were similar between the two cohorts of patients (p = .17 and p = .40, respectively). Local control rate was 96% and 81% for patients treated with MB approach and IMRT-only, respectively.Conclusions: Sequential MB approach for LANPC patients provides a significantly lower acute toxicity profile compared to full course of IMRT. There were no differences in early-late morbidities and disease-related outcomes (censored at two-years) but a longer follow-up is required to achieve conclusive results.
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Affiliation(s)
- Daniela Alterio
- Division of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy
| | - Emma D’Ippolito
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Barbara Vischioni
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Piero Fossati
- Division of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Sara Gandini
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Milan, Italy
| | - Maria Bonora
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Sara Ronchi
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Viviana Vitolo
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Edoardo Mastella
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Giuseppe Magro
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | | | - Umberto Ricardi
- Department of Oncology, Radiation Oncology, University of Torino, Turin, Italy
| | - Marco Krengli
- Department of Translational Medicine, Novara, University of Piemonte Orientale, Vercelli, Italy
| | - Giovanni Ivaldi
- Unit of Radiation Oncology, ICS Maugeri, IRCSS, Pavia, Italy
| | - Annamaria Ferrari
- Division of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy
| | - Giuseppi Fanetti
- Division of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy
| | - Stefania Comi
- Unit of Medical Physics, European Institute of Oncology, Milan, Italy
| | - Marta Tagliabue
- Department of Head and Neck Surgery and Otorhinolaryngology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Elena Verri
- Department of Medical Oncology, European Institute of Oncology, Milan, Italy
| | - Rosalinda Ricotti
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Delia Ciardo
- Division of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy
| | - Barbara Alicja Jereczek-Fossa
- Division of Radiation Oncology, European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy
| | - Francesca Valvo
- Radiation Oncology Clinical Department, National Center of Oncological Hadrontherapy, Pavia, Italy
| | - Roberto Orecchia
- Scientific Direction, European Institute of Oncology IRCCS, Milan, Italy
- Scientific Direction, National Center of Oncological Hadrontherapy, Pavia, Italy
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27
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Aoyama T, Shimizu H, Isomura T, Kitagawa T, Tanaka K, Kodaira T. [Development of an In-house Couch Model to Improve Dose Attenuation Correction Accuracy for a Couch with Different Thickness in the Superior-inferior Direction]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2019; 75:1125-1134. [PMID: 31631105 DOI: 10.6009/jjrt.2019_jsrt_75.10.1125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
As the couch used in external radiation therapy attenuate radiation by interaction, it is necessary to correct attenuation of radiation by inserting a couch model in the treatment planning systems. For a couch whose thickness is different in the superior-inferior direction, it is possible to perform dose calculations with an error within ±1% by using separate different couch models provided by vendors. However, it is difficult to correct attenuation correction accurately with a single couch model. In this study, we created an in-house couch model which can set couch shape and physical density in detail by acquiring CT images of actual couch. When we performed dose calculation by optimizing the physical densities of in-house and vendor couch, it was found that the difference between the measured and the calculated values can be significantly reduced by using in-house couch model. Additionally, by using in-house couch model, it is found that the dose attenuation can be corrected within ±1% for a couch whose thickness is different in the superior-inferior direction.
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Affiliation(s)
- Takahiro Aoyama
- Department of Radiation Oncology, Aichi Cancer Center Hospital
| | - Hidetoshi Shimizu
- Department of Radiation Oncology, Aichi Cancer Center Hospital.,Graduate School of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Taiki Isomura
- Department of Radiation Oncology, Aichi Cancer Center Hospital (Current address: Department of Proton Technology, Medipolis Proton Therapy and Research Center)
| | - Tomoki Kitagawa
- Department of Radiation Oncology, Aichi Cancer Center Hospital
| | - Kento Tanaka
- Department of Radiation Oncology, Aichi Cancer Center Hospital (Current address: Department of Radiology, Okazaki City Hospital)
| | - Takeshi Kodaira
- Department of Radiation Oncology, Aichi Cancer Center Hospital
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28
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Buckley JG, Rai R, Liney GP, Dowling JA, Holloway LC, Metcalfe PE, Keall PJ. Anatomical deformation due to horizontal rotation: towards gantry-free radiation therapy. ACTA ACUST UNITED AC 2019; 64:175014. [DOI: 10.1088/1361-6560/ab324c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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29
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Bawazeer O, Herath S, Sarasanandarajah S, Kron T, Dunn L, Deb P. A simple and efficient method to measure beam attenuation through a radiotherapy treatment couch and immobilization devices. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:1183-1189. [PMID: 31452056 DOI: 10.1007/s13246-019-00789-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 08/09/2019] [Indexed: 11/29/2022]
Abstract
We propose a simple and efficient method to measure beam attenuation in one or two dimensions using an amorphous silicon electronic portal imaging device (a-Si EPID). The proposed method was validated against ionization chamber measurements. Beam attenuation through treatment couches (Varian Medical Systems) and immobilization devices (CIVCO Radiotherapy, USA) was examined. The dependency of beam attenuation on field size, photon energy, thickness of the couch, and the presence of a phantom were studied. Attenuation images were derived by computing the percentage difference between images obtained without and with a couch or immobilization devices determining the percentage of attenuation at the center and the mean attenuation. The beam attenuation measurements obtained with an a-Si EPID and an ionization chamber agreed to within ± 0.10 to 1.80%. No difference was noted between the center and mean of an attenuated image for a small field size of 5 × 5 cm2, whereas a large field size of 15 × 15 cm2 exhibited differences of up to 1.13%. For an 18 MV beam, the a-Si EPID required additional build-up material for accurate assessment of beam attenuation. The a-Si EPID could measure differences in beam attenuation through an image guided radiotherapy (IGRT) couch regardless of the variabilities in couch thickness. Interestingly, the addition of a phantom reduced the magnitude of attenuation by approximately 1.20% for a field size of 15 × 15 cm2. A simple method is proposed that provides the user with beam attenuation data in either 2D or 1D within a few minutes.
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Affiliation(s)
- Omemh Bawazeer
- Discipline of Medical Radiations, RMIT University, Melbourne, Australia. .,Discipline of Sciences, Umm Al-Qura University, Mecca, Saudi Arabia.
| | - Sisira Herath
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - Sivananthan Sarasanandarajah
- Discipline of Medical Radiations, RMIT University, Melbourne, Australia.,Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia.,Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Australia
| | - Tomas Kron
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia.,Sir Peter MacCallum Cancer Institute, University of Melbourne, Melbourne, Australia
| | - Leon Dunn
- Epworth Radiation Oncology, Epworth Hospital, Melbourne, Australia
| | - Pradip Deb
- Discipline of Medical Radiations, RMIT University, Melbourne, Australia
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30
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Okada W, Tanooka M, Sano K, Shibata M, Doi H, Miyazaki M, Nakahara R, Sueoka M, Suzuki H, Fujiwara M, Inomata T, Yamakado K. Couch modeling optimization for tomotherapy planning and delivery. J Appl Clin Med Phys 2019; 20:114-121. [PMID: 31343831 PMCID: PMC6698767 DOI: 10.1002/acm2.12686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/26/2019] [Accepted: 07/07/2019] [Indexed: 11/08/2022] Open
Abstract
We sought to validate new couch modeling optimization for tomotherapy planning and delivery. We constructed simplified virtual structures just above a default setting couch through a planning support system (MIM Maestro, version 8.2, MIM Software Inc, Cleveland, OH, USA). Based on ionization chamber measurements, we performed interactive optimization and determined the most appropriate physical density of these virtual structures in a treatment planning system (TPS). To validate this couch optimization, Gamma analysis and these statistical analyses between a three‐dimensional diode array QA system (ArcCHECK, Sun Nuclear, Melbourne, FL, USA) results and calculations from ionization chamber measurements were performed at 3%/2 mm criteria with a threshold of 10% in clinical QA plans. Using a virtual model consisting of a center slab density of 4.2 g/cm3 and both side slabs density of 1.9 g/cm3, we demonstrated close agreement between measured dose and the TPS calculated dose. Agreement was within 1% for all gantry angles at the isocenter and within 2% in off‐axis plans. In validation of the couch modeling in a clinical QA plan, the average gamma passing rate improved approximately 0.6%–5.1%. It was statistically significant (P < 0.05) for all treatment sites. We successfully generated an accurate couch model for a TomoTherapy TPS by interactively optimizing the physical density of the couch using a planning support system. This modeling proved to be an efficient way of correcting the dosimetric effects of the treatment couch in tomotherapy planning and delivery.
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Affiliation(s)
- Wataru Okada
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan.,Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Japan
| | - Masao Tanooka
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan.,Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Japan
| | - Keisuke Sano
- Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Japan
| | - Mayuri Shibata
- Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Japan
| | - Hiroshi Doi
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan.,Department of Radiation Oncology, Kindai University Faculty of Medicine, Sayama, Japan
| | | | - Ryuta Nakahara
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Masaki Sueoka
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Hitomi Suzuki
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Masayuki Fujiwara
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan
| | - Taisuke Inomata
- Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Japan
| | - Koichiro Yamakado
- Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan
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31
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Tanabe Y. [7. Installation and Acceptance Testing for Radiotherapy Treatment Planning Systems]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2019; 75:201-210. [PMID: 30787227 DOI: 10.6009/jjrt.2019_jsrt_75.2.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Yoshinori Tanabe
- Department of Radiological Technology, Yamaguchi University Hospital
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32
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Matsumoto K, Saika T, Shimomura K, Hanaoka K, Tamura M, Monzen H, Hayakawa M, Okumura M. [Development of Novel Immobilization Adapter for Head and Neck Radiotherapy with Low-attenuation Material]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2019; 75:167-173. [PMID: 30787223 DOI: 10.6009/jjrt.2019_jsrt_75.2.167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
PURPOSE The dosimetric error due to immobilization devices has been highlighted by the AAPM Task Group 176. We developed a novel low-radiation-absorbent immobilization adaptor (HMA), which can be used with a Styrofoam headrest for head and neck region in radiotherapy. The purpose of this study was to investigate the impact of the HMA on the dose distribution and compare with a commercially released plastic adapter. METHODS Computed tomography (CT) simulation and dose calculation on a treatment planning system (TPS) were performed by the use of HMA and the plastic adapter with a cylindrical phantom. Both the adapters were placed on the phantom upside and the attenuation rate was measured. Gantry angles were changed at every 1°interval from 0°to 50°for measurements. The measured dose was normalized by the value of 90°. The treatment equipment was TrueBeam (Varian medical systems); X-ray energies were set on 4, 6 and 10 MV, respectively. The measured attenuation rates were also compared with calculation results of TPS. RESULTS The highest differences on attenuation rate of both the adapters were observed at a gantry angle of 32.0°; the differences were 3.0% at 4 MV, 2.7% at 6 MV and 3.0% at 10 MV, respectively, and lower absorption was HMA. TPS calculation results of monitor unit for the HMA were within 1.0% in each energy. CONCLUSION The HMA was able to provide absorption dose and calculation errors lower than a commercially released adapter. It can also provide more accurate dose delivery for radiotherapy in head and neck because of the low absorption characteristics.
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Affiliation(s)
| | | | | | | | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Science, Kindai University
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Science, Kindai University
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Stambaugh C, Gagneur J, Uejo A, Clouser E, Ezzell G. Improvements in treatment planning calculations motivated by tightening IMRT QA tolerances. J Appl Clin Med Phys 2018; 20:250-257. [PMID: 30599085 PMCID: PMC6333129 DOI: 10.1002/acm2.12524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/22/2018] [Accepted: 12/02/2018] [Indexed: 11/21/2022] Open
Abstract
Implementing tighter intensity modulated radiation therapy (IMRT) quality assurance (QA) tolerances initially resulted in high numbers of marginal or failing QA results and motivated a number of improvements to our calculational processes. This work details those improvements and their effect on results. One hundred eighty IMRT plans analyzed previously were collected and new gamma criteria were applied and compared to the original results. The results were used to obtain an estimate for the number of plans that would require additional dose volume histogram (DVH)‐based analysis and therefore predicted workload increase. For 2 months and 133 plans, the established criteria were continued while the new criteria were applied and tracked in parallel. Because the number of marginal or failing plans far exceeded the predicted levels, a number of calculational elements were investigated: IMRT modeling parameters, calculation grid size, and couch top modeling. After improvements to these elements, the new criteria were clinically implemented and the frequency of passing, questionable, and failing plans measured for the subsequent 15 months and 674 plans. The retrospective analysis of selected IMRT QA results demonstrated that 75% of plans should pass, while 19% of IMRT QA plans would need DVH‐based analysis and an additional 6% would fail. However, after applying the tighter criteria for 2 months, the distribution of plans was significantly different from prediction with questionable or failing plans reaching 47%. After investigating and improving several elements of the IMRT calculation processes, the frequency of questionable plans was reduced to 11% and that of failing plans to less than 1%. Tighter IMRT QA tolerances revealed the need to improve several elements of our plan calculations. As a consequence, the accuracy of our plans have improved, and the frequency of finding marginal or failing IMRT QA results, remains within our practical ability to respond.
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Affiliation(s)
- Cassandra Stambaugh
- Department of Radiation Oncology, Tufts Medical Center, Boston, MA, 02111, USA
| | - Justin Gagneur
- Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, AZ, 85054, USA
| | - Arielle Uejo
- Department of Radiation Oncology, Karmanos cancer Center at McLaren Flint, Flint, MI, 48532, USA
| | - Edward Clouser
- Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, AZ, 85054, USA
| | - Gary Ezzell
- Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, AZ, 85054, USA
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Sdrolia A, Tambe N, Marsden JE, Wilson ML, Colley WP, Beavis AW. Investigation of the bolusing effect of the Varian Exact
TM
IGRT couch on flattened and flattening filter-free (FFF) photon beams of a Varian TrueBeam linac. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aaeb11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ferrer C, Huertas C, Plaza R, Aza Z, Corredoira E. Dosimetric effects of a repositioning head frame system and treatment planning system dose calculation accuracy. J Appl Clin Med Phys 2018; 19:124-132. [PMID: 30255659 PMCID: PMC6236818 DOI: 10.1002/acm2.12456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/16/2018] [Accepted: 08/26/2018] [Indexed: 11/29/2022] Open
Abstract
This work aims to study the effect on surface dose and dose distribution caused by the Elekta Fraxion cranial immobilization system. The effect of Fraxion inclusion in Elekta Monaco treatment planning system and its calculation accuracy is also checked. To study the dose attenuation, a cylindrical phantom was located over the Elekta Fraxion with an IBA CC13 ionization chamber placed in the central insert at the linac isocenter. Dose measurements at multiple gantry angles were performed for three open fields, 10 × 10 cm, 5 × 5 cm and other smaller 2 × 2 cm. Measured doses were compared with the ones calculated by Monaco. Surface dose and dose distribution in the buildup region were measured placing several Gafchromic Films EBT3 at linac CAX between the slabs of a RW3 phantom located over Fraxion and read using FilmQA Pro software. Measures were performed for two open field sizes and results were compared with Monaco calculations. Measurements show a 1% attenuation for 180° gantry angle but it can be as high as 3.4% (5 × 5 open field) for 150°/210° gantry angle, as with these angles the beam goes through the Fraxion's headrest twice. If Fraxion is not included in the calculation Monaco calculation can result in a 3% difference between measured and calculated doses, while with Fraxion in the calculation, the maximum difference is 0.9%. Fraxion increases 3.7 times the surface dose, which can be calculated by Monaco with a difference lower than 2%. Monaco also calculated correctly the PDD for both open fields (2%) when Fraxion is included in the calculation. This work shows that the attenuation varies with gantry angle. The inclusion of Fraxion in Monaco improves the calculation from 3% difference to 1% in the worst case. Furthermore, the surface dose increment and the dose in the buildup region are correctly calculated.
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Affiliation(s)
- Carlos Ferrer
- Department of Medical Physics and Radiation Protection; H.U. La Paz; Madrid Spain
| | - Concepción Huertas
- Department of Medical Physics and Radiation Protection; H.U. La Paz; Madrid Spain
| | - Rodrigo Plaza
- Department of Medical Physics and Radiation Protection; H.U. La Paz; Madrid Spain
| | - Zulima Aza
- Department of Medical Physics and Radiation Protection; H.U. La Paz; Madrid Spain
| | - Eva Corredoira
- Department of Medical Physics and Radiation Protection; H.U. La Paz; Madrid Spain
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Kairn T. Patient rotation during linac-based photon electron radiotherapy. J Med Imaging Radiat Oncol 2018; 62:548-552. [PMID: 29984558 DOI: 10.1111/1754-9485.12757] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 05/26/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Tanya Kairn
- Cancer Care Services, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
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Meyer T, Quirk S, D'Souza M, Spencer D, Roumeliotis M. A framework for clinical commissioning of 3D-printed patient support or immobilization devices in photon radiotherapy. J Appl Clin Med Phys 2018; 19:499-505. [PMID: 29984551 PMCID: PMC6123103 DOI: 10.1002/acm2.12408] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/29/2018] [Accepted: 06/05/2018] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The objective of this work is to outline a framework for dosimetric characterization that will comprehensively detail the clinical commissioning steps for 3D-printed materials applied as patient support or immobilization devices in photon radiotherapy. The complex nature of 3D-printed materials with application to patient-specific configurations requires careful consideration. The framework presented is generalizable to any 3D-printed object where the infill and shell combinations are unknown. METHODS A representative cylinder and wedge were used as test objects to characterize devices that may be printed of unknown, patient-specific dimensions. A case study of a 3D-printed CSI immobilization board was presented as an example of an object of known, but adaptable dimensions and proprietary material composition. A series of measurements were performed to characterize the material's kV radiologic properties, MV attenuation measurements and calculations, energy spectrum water equivalency, and surface dose measurements. These measurements complement the recommendations of the AAPM's TG176 to characterize the additional complexity of 3D-printed materials for use in a clinical radiotherapy environment. RESULTS The dosimetric characterization of 3D-printed test objects and a case study device informed the development of a step-by-step template that can easily be followed by clinicians to accurately and safely utilize 3D-printed materials as patient-specific support or immobilization devices. CONCLUSIONS A series of steps is outlined to provide a formulaic approach to clinically commission 3D-printed materials that may possess varying material composition, infill patterns, and patient-specific dimensions.
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Affiliation(s)
- Tyler Meyer
- Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Sarah Quirk
- Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Malgorzata D'Souza
- Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - David Spencer
- Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Michael Roumeliotis
- Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, Canada
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Tyran M, Tallet A, Resbeut M, Ferre M, Favrel V, Fau P, Moureau-Zabotto L, Darreon J, Gonzague L, Benkemouche A, Varela-Cagetti L, Salem N, Farnault B, Acquaviva MA, Mailleux H. Safety and benefit of using a virtual bolus during treatment planning for breast cancer treated with arc therapy. J Appl Clin Med Phys 2018; 19:463-472. [PMID: 29959819 PMCID: PMC6123145 DOI: 10.1002/acm2.12398] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 12/19/2022] Open
Abstract
Purpose This study evaluates the benefit of a virtual bolus method for volumetric modulated arc therapy (VMAT) plan optimization to compensate breast modifications that may occur during breast treatment. Methods Ten files were replanned with VMAT giving 50 Gy to the breast and 47 Gy to the nodes within 25 fractions. The planning process used a virtual bolus for the first optimization, then the monitors units were reoptimized without bolus, after fixing the segments shapes. Structures and treatment planning were exported on a second scanner (CT) performed during treatment as a consequence to modifications in patient's anatomy. The comparative end‐point was clinical target volume's coverage. The first analysis compared the VMAT plans made using the virtual bolus method (VB‐VMAT) to the plans without using it (NoVB‐VMAT) on the first simulation CT. Then, the same analysis was performed on the second CT. Finally, the level of degradation of target volume coverage between the two CT using VB‐VMAT was compared to results using a standard technique of forward‐planned multisegment technique (Tan‐IMRT). Results Using a virtual bolus for VMAT does not degrade dosimetric results on the first CT. No significant result in favor of the NoVB‐VMAT plans was noted. The VB‐VMAT method led to significant better dose distribution on a second CT with modified anatomies compared to NoVB‐VMAT. The clinical target volume's coverage by 95% (V95%) of the prescribed dose was 98.9% [96.1–99.6] on the second CT for VB‐VMAT compared to 92.6% [85.2–97.7] for NoVB‐VMAT (P = 0.0002). The degradation of the target volume coverage for VB‐VMAT is not worse than for Tan‐IMRT: the median differential of V95% between the two CT was 0.9% for VMAT and 0.7% for Tan‐IMRT (P = 1). Conclusion This study confirms the safety and benefit of using a virtual bolus during the VMAT planning process to compensate potential breast shape modifications.
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Affiliation(s)
- Marguerite Tyran
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Agnes Tallet
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Michel Resbeut
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Marjorie Ferre
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Veronique Favrel
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Pierre Fau
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | | | - Julien Darreon
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Laurence Gonzague
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Ahcene Benkemouche
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | | | - Naji Salem
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | - Bertrand Farnault
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
| | | | - Hugues Mailleux
- Department of Radiation-Oncology, Institut Paoli-Calmettes, Marseille, France
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Rijken J, Kairn T, Crowe S, Muñoz L, Trapp J. A simple method to account for skin dose enhancement during treatment planning of VMAT treatments of patients in contact with immobilization equipment. J Appl Clin Med Phys 2018; 19:239-245. [PMID: 29934993 PMCID: PMC6036355 DOI: 10.1002/acm2.12394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/29/2018] [Accepted: 06/01/2018] [Indexed: 12/31/2022] Open
Abstract
Purpose The ability to accurately predict skin doses and thereby design radiotherapy treatments that balance the likelihood of skin reactions against other treatment objectives is especially important when hypofractionated prescription regimes are used. However, calculations of skin dose provided by many commercial radiotherapy treatment planning systems are known to be inaccurate, especially if the presence of immobilization equipment is not accurately taken into account. This study proposes a simple method by which the accuracy of skin dose calculations can be substantially improved, to allow informed evaluation of volumetric modulated arc therapy (VMAT) treatment plans. Method A simple method was developed whereby dose calculation is split into grid regions, each with a correction factor which determines MU scaling for skin dose calculation. Correction factors were derived from film measurements made using a geometrically simple phantom in partial contact with a vacuum immobilization device. This method was applied to two different test treatments, planned for delivery to a humanoid phantom with a hypofractionated stereotactic body radiotherapy technique, and results were verified using film measurements of surface dose. Results Compared to the measured values, calculations of skin dose volumes corresponding to different grade tissue reactions were greatly improved through use of the method employed in this study. In some cases, the accuracy of skin dose evaluation improved by 76% and brought values to within 3% of those measured. Conclusion The method of skin dose calculation in this study is simple, can be made as accurate as the user requires and is applicable for various immobilization systems. This concept has been verified through use on SBRT lung treatment plans and will aid clinicians in predicting skin response in patients.
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Affiliation(s)
- James Rijken
- Genesis Care, Flinders Private Hospital, Bedford Park, SA, Australia.,Queensland University of Technology, Brisbane, QLD, Australia
| | - Tanya Kairn
- Queensland University of Technology, Brisbane, QLD, Australia.,Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Scott Crowe
- Queensland University of Technology, Brisbane, QLD, Australia.,Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Luis Muñoz
- Genesis Care, Flinders Private Hospital, Bedford Park, SA, Australia
| | - Jamie Trapp
- Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
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Snyder KC, Xhaferllari I, Huang Y, Siddiqui MS, Chetty IJ, Wen N. Evaluation and verification of the QFix Encompass TM couch insert for intracranial stereotactic radiosurgery. J Appl Clin Med Phys 2018; 19:222-229. [PMID: 29905000 PMCID: PMC6036407 DOI: 10.1002/acm2.12387] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/02/2018] [Accepted: 05/16/2018] [Indexed: 11/11/2022] Open
Abstract
The QFix EncompassTM stereotactic radiosurgery (SRS) immobilization system consists of a thermoplastic mask that attaches to the couch insert to immobilize patients treated with intracranial SRS. This study evaluates the dosimetric impact and verifies a vendor provided treatment planning system (TPS) model in the Eclipse TPS. A thermoplastic mask was constructed for a Lucy 3D phantom, and was scanned with and without the EncompassTM system. Attenuation measurements were performed in the Lucy phantom with and without the insert using a pinpoint ion chamber for energies of 6xFFF, 10xFFF and 6X, with three field sizes (2 × 2, 4 × 4, and 6 × 6 cm2 ). The measurements were compared to two sets of calculations. The first set utilized the vendor provided Encompass TPS model (EncompassTPS ), which consists of two structures: the Encompass and Encompass base structure. Three HU values for the Encompass (200, 300, 400) and Encompass Base (-600, -500, -400) structures were evaluated. The second set of calculations consists of the Encompass insert included in the external body contour (EncompassEXT ) for dose calculation. The average measured percent attenuation in the posterior region of the insert ranged from 3.4%-3.8% for the 6xFFF beam, 2.9%-3.4% for the 10xFFF, and 3.3%-3.6% for the 6X beam. The maximum attenuation occurred at the region where the mask attaches to the insert, where attenuation up to 17% was measured for a 6xFFF beam. The difference between measured and calculated attenuation with either the EncompassEXT or EncompassTPS approach was within 0.5%. HU values in the EncompassTPS model that provided the best agreement with measurement was 400 for the Encompass structure and -400 for the Encompass base structure. Significant attenuation was observed at the area where the mask attaches to the insert. Larger differences can be observed when using few static beams compared to rotational treatment techniques.
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Affiliation(s)
- Karen Chin Snyder
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Ilma Xhaferllari
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Yimei Huang
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - M Salim Siddiqui
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Indrin J Chetty
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
| | - Ning Wen
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, USA
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Chen L, Peng YL, Gu SY, Shen H, Zhang DD, Sun WZ, Wu JH, Deng XW. Dosimetric Effects of Head and Neck Immobilization Devices on Multi-field Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma. J Cancer 2018; 9:2443-2450. [PMID: 30026841 PMCID: PMC6036882 DOI: 10.7150/jca.24887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/01/2018] [Indexed: 11/11/2022] Open
Abstract
Background: In practice, the dose perturbation effect of head and neck immobilization devices is often overlooked in intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC). Purpose of this study is to verify and analyze the dosimetric effect of head and neck immobilization devices on NPC multi-field IMRT. Methods: Ten patients with nasopharyngeal carcinoma were randomly selected. Two sets of body contours were established for each patient. One set of body contours did not contain the immobilization device, and the other contour set included the immobilization device. For each patient, dose calculations were conducted for the two sets of contours using the same 9-field IMRT plan, which were recorded as Plan- and Plan+. The dose difference caused by the head and neck immobilization devices was assessed by comparing the dose-volume histogram (DVH) parameter results and by plan subtraction. The gafchromic EBT3 film and anthropomorphic phantom were used to verify the calculated doses. Results: The target coverage and average dose of Plan+ were lower than those of Plan- : the prescription dose coverage rates for PTVnx, PTVnd, PTV1 and PTV2 decreased by 2.4%, 9.9%, 1.5%, and 3.6%, respectively, and the mean doses were reduced by 0.9%, 1.9%, 1.1%, and 1.5%, respectively. Doses in the organs at risk showed no significant differences or slight reductions (the maximum reduction in mean dose was 1.7%). From the EBT3 measurements, the skin dose on the posterior neck was increased by approximately 53%. Conclusion: The attenuation and bolus effects of the head and neck immobilization device reduce dose coverage rate and average dose of the planning target volumes in nasopharyngeal carcinoma and lead to an increase in the skin dose. During treatment planning and dose calculation, the immobilization device should be included within body contour to account for the dose attenuation and skin dose increment.
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Affiliation(s)
- Li Chen
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Ying-Lin Peng
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Shi-Yong Gu
- Department of Radiation Oncology, Wuhan General Hospital of Guangzhou Military, No. 627, Wuluo Road, Hongshan District, Wuhan 430064, China
| | - Hui Shen
- Department of Radiation Oncology, Yangjiang Hospital, No.42, Dongshan Road, Jiangcheng District, Yangjiang 529599, China
| | - Dan-Dan Zhang
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Wen-Zhao Sun
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Jian-Hua Wu
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Xiao-Wu Deng
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
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Guebert A, Conroy L, Weppler S, Alghamdi M, Conway J, Harper L, Phan T, Olivotto IA, Smith WL, Quirk S. Clinical implementation of AXB from AAA for breast: Plan quality and subvolume analysis. J Appl Clin Med Phys 2018; 19:243-250. [PMID: 29696752 PMCID: PMC5978944 DOI: 10.1002/acm2.12329] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/06/2017] [Accepted: 03/02/2018] [Indexed: 12/01/2022] Open
Abstract
Purpose Two dose calculation algorithms are available in Varian Eclipse software: Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB). Many Varian Eclipse‐based centers have access to AXB; however, a thorough understanding of how it will affect plan characteristics and, subsequently, clinical practice is necessary prior to implementation. We characterized the difference in breast plan quality between AXB and AAA for dissemination to clinicians during implementation. Methods Locoregional irradiation plans were created with AAA for 30 breast cancer patients with a prescription dose of 50 Gy to the breast and 45 Gy to the regional node, in 25 fractions. The internal mammary chain (IMCCTV) nodes were covered by 80% of the breast dose. AXB, both dose‐to‐water and dose‐to‐medium reporting, was used to recalculate plans while maintaining constant monitor units. Target coverage and organ‐at‐risk doses were compared between the two algorithms using dose–volume parameters. An analysis to assess location‐specific changes was performed by dividing the breast into nine subvolumes in the superior–inferior and left–right directions. Results There were minimal differences found between the AXB and AAA calculated plans. The median difference between AXB and AAA for breastCTVV95%, was <2.5%. For IMCCTV, the median differences V95%, and V80% were <5% and 0%, respectively; indicating IMCCTV coverage only decreased when marginally covered. Mean superficial dose increased by a median of 3.2 Gy. In the subvolume analysis, the medial subvolumes were “hotter” when recalculated with AXB and the lateral subvolumes “cooler” with AXB; however, all differences were within 2 Gy. Conclusion We observed minimal difference in magnitude and spatial distribution of dose when comparing the two algorithms. The largest observable differences occurred in superficial dose regions. Therefore, clinical implementation of AXB from AAA for breast radiotherapy is not expected to result in changes in clinical practice for prescribing or planning breast radiotherapy.
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Affiliation(s)
- Alexandra Guebert
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada
| | - Leigh Conroy
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Division of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Sarah Weppler
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Division of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Majed Alghamdi
- Division of Radiation Oncology, Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Jessica Conway
- Division of Radiation Oncology, Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Lindsay Harper
- Department of Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Tien Phan
- Division of Radiation Oncology, Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Ivo A Olivotto
- Division of Radiation Oncology, Department of Oncology, University of Calgary, Calgary, AB, Canada.,Department of Oncology, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Wendy L Smith
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Division of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada.,Division of Radiation Oncology, Department of Oncology, University of Calgary, Calgary, AB, Canada
| | - Sarah Quirk
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Division of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada.,Division of Radiation Oncology, Department of Oncology, University of Calgary, Calgary, AB, Canada
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Aznar MC, Warren S, Hoogeman M, Josipovic M. The impact of technology on the changing practice of lung SBRT. Phys Med 2018; 47:129-138. [PMID: 29331227 PMCID: PMC5883320 DOI: 10.1016/j.ejmp.2017.12.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 11/20/2017] [Accepted: 12/23/2017] [Indexed: 02/09/2023] Open
Abstract
Stereotactic body radiotherapy (SBRT) for lung tumours has been gaining wide acceptance in lung cancer. Here, we review the technological evolution of SBRT delivery in lung cancer, from the first treatments using the stereotactic body frame in the 1990's to modern developments in image guidance and motion management. Finally, we discuss the impact of current technological approaches on the requirements for quality assurance as well as future technological developments.
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Affiliation(s)
- Marianne Camille Aznar
- Clinical Trial Service Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK; Institute for Clinical Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
| | - Samantha Warren
- Hall Edwards Radiotherapy Group, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Mischa Hoogeman
- MC-Daniel den Hoed Cancer Center, Erasmus University, Rotterdam, Netherlands
| | - Mirjana Josipovic
- Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Department of Oncology, Section for Radiotherapy, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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Wang L, Cmelak AJ, Ding GX. A simple technique to improve calculated skin dose accuracy in a commercial treatment planning system. J Appl Clin Med Phys 2018; 19:191-197. [PMID: 29411506 PMCID: PMC5849836 DOI: 10.1002/acm2.12275] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 12/18/2017] [Accepted: 01/02/2018] [Indexed: 11/15/2022] Open
Abstract
Radiation dermatitis during radiotherapy is correlated with skin dose and is a common clinical problem for head and neck and thoracic cancer patients. Therefore, accurate prediction of skin dose during treatment planning is clinically important. The objective of this study is to evaluate the accuracy of skin dose calculated by a commercial treatment planning system (TPS). We evaluated the accuracy of skin dose calculations by the anisotropic analytical algorithm (AAA) implemented in Varian Eclipse (V.11) system. Skin dose is calculated as mean dose to a contoured structure of 0.5 cm thickness from the surface. The EGSnrc Monte Carlo (MC) simulations are utilized for the evaluation. The 6, 10 and 15 MV photon beams investigated are from a Varian TrueBeam linear accelerator. The accuracy of the MC dose calculations was validated by phantom measurements with optically stimulated luminescence detectors. The calculation accuracy of patient skin doses is studied by using CT based radiotherapy treatment plans including 3D conformal, static gantry IMRT, and VMAT treatment techniques. Results show the Varian Eclipse system underestimates skin doses by up to 14% of prescription dose for the patients studied when external body contour starts at the patient's skin. The external body contour is used in a treatment planning system to calculate dose distributions. The calculation accuracy of skin dose with Eclipse can be considerably improved to within 4% of target dose by extending the external body contour by 1 to 2 cm from the patient's skin. Dose delivered to deeper target volumes or organs at risk are not affected. Although Eclipse treatment planning system has its limitations in predicting patient skin dose, this study shows the calculation accuracy can be considerably improved to an acceptable level by extending the external body contour without affecting the dose calculation accuracy to the treatment target and internal organs at risk. This is achieved by moving the calculation entry point away from the skin.
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Affiliation(s)
- Lilie Wang
- Department of Radiation OncologyVanderbilt University Medical CenterNashvilleTN37232USA
| | - Anthony J. Cmelak
- Department of Radiation OncologyVanderbilt University Medical CenterNashvilleTN37232USA
| | - George X. Ding
- Department of Radiation OncologyVanderbilt University Medical CenterNashvilleTN37232USA
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Olaciregui-Ruiz I, Rozendaal R, Mijnheer B, Mans A. A 2D couch attenuation model for
in vivo
EPID transit dosimetry. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aaa370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Olson A, Phillips K, Eng T, Lenards N, Hunzeker A, Lewis D, Baumann D. Assessing dose variance from immobilization devices in VMAT head and neck treatment planning: A retrospective case study analysis. Med Dosim 2018; 43:39-45. [DOI: 10.1016/j.meddos.2017.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/08/2017] [Indexed: 11/28/2022]
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Tuğrul T. Absorption ratio of treatment couch and effect on surface and build-up region doses. Rep Pract Oncol Radiother 2017; 23:1-5. [PMID: 29187806 DOI: 10.1016/j.rpor.2017.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/29/2017] [Indexed: 10/18/2022] Open
Abstract
Aim In this study, at different fields, energies and gantry angles, treatment couch and rails dose absorption ratio and treatment couch effect on surface and build-up region doses were examined. Background It is assumed that radiation attenuation is minimal because the carbon fiber couches have low density and it is not generally accounted for during treatment planning. Consequently, it leads to a major dosimetric mistake. Materials and methods Solid water phantom was used for relative dose measurement. The measurements were done using a Farmer ion chamber with 0.6 cc volume and a parallel plane ion chamber starting from surface with 1 mm depth intervals at 10 × 10 cm2 field, SSD 100 cm. Measurements were taken for situations where the beams intersect the couch and couch rails. Results Dose absorption ratio of carbon fiber couch obtained at gantry angle of 180° was 1.52%, 0.69%, 0.33% and 0.25% at different field sizes for 6 MV. For 15 MV, this ratio was 0.95%, 0.27%, 0.20% and 0.05%. The absorption ratio is between 3.4% and 1.22% when the beams intersect with couch rails. The couch effect increased surface dose from 14% to 70% for 6 MV and from 11.34% to 53.03% for 15 MV. Conclusions The results showed that the carbon fiber couch increased surface dose during posterior irradiation. Therefore, the skin-sparing effect of the high energy beams was decreased. If the effect of couch is not considered, it may cause significant differences at dose which reaches the patient and may cause tissue problems such as erythema.
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Affiliation(s)
- Taylan Tuğrul
- Radiation Oncology Department, Yüzüncü Yıl University, Van, Turkey
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Zhang R, Gao Y, Bai W. Quantification and comparison the dosimetric impact of two treatment couch model in VMAT. J Appl Clin Med Phys 2017; 19:10-16. [PMID: 29094802 PMCID: PMC5768035 DOI: 10.1002/acm2.12206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 11/15/2022] Open
Abstract
The use of Monte Carlo treatment planning systems (TPS) in radiation therapy has increased the dosimetric accuracy of VMAT treatment sequences. However, this accuracy is compromised by not including the treatment couch into the treatment planning process. Therefore, the impact of the treatment couch on radiation delivery output was determined, and two different couch models (uniform couch model A vs two components model B) were included and tested in the Monaco TPS to investigate which model can better quantify the couch influence on radiation dose. Relative attenuation measurements were performed following procedures outlined by TG‐176 with three phantom positions for A–B direction: on the left half (L), in the center (C) and on the right half (R) of the couch. As well as absolute dose comparison of static fields of 10 × 10 cm2 that were delivered through the couch tops with that calculated in the TPS with the couch model at 2 mm and 5 mm computing grid size respectively. The most severe percentage deviation was 4.60% for the phantom positioned at the left half of the couch with 5 mm grid size at gantry angle 120°. The couch model was included in the TPS with a uniform ED of 0.26 g/cm3 or a two component model with a fiber 0.52 g/cm3 and foam core 0.1 g/cm3. After including the treatment couch, the maximum mean dose attenuation was reduced from 3.68% without couch included to (0.60, 0.83, 0.72, and 1.02) % for model A and model B at 2 and 5 mm voxel grid size. The results obtained showed that Model A performed better than the model B, demonstrating lower deviations from measurements and better robustness against dose grid resolution changes. Considering the results of this study, we propose the systematic introduction of the couch Model A in clinical routine. All the reported findings are valid for the Elekta iBEAM® evo Extension 415 couch and these methods can also be used for other couch model.
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Affiliation(s)
- Ruohui Zhang
- Department of Biomedical Engineering, Tianjin University, Tianjin, China.,Department of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yulan Gao
- Department of Gastroenterology, Hebei General Hospital, Shijiazhuang, China
| | - Wenwen Bai
- Department of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
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Cheung JP, Perez-Andujar A, Morin O. Characterization of the effect of a new commercial transmission detector on radiation therapy beams. Pract Radiat Oncol 2017; 7:e559-e567. [PMID: 28666901 DOI: 10.1016/j.prro.2017.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 03/07/2017] [Accepted: 04/05/2017] [Indexed: 10/19/2022]
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Varfalvy N, Piron O, Cyr MF, Dagnault A, Archambault L. Classification of changes occurring in lung patient during radiotherapy using relative γ analysis and hidden Markov models. Med Phys 2017; 44:5043-5050. [PMID: 28744863 DOI: 10.1002/mp.12488] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To present a new automated patient classification method based on relative gamma analysis and hidden Markov models (HMM) to identify patients undergoing important anatomical changes during radiation therapy. METHODS Daily EPID images of every treatment field were acquired for 52 patients treated for lung cancer. In addition, CBCT were acquired on a regular basis. Gamma analysis was performed relative to the first fraction given that no significant anatomical change was observed on the CBCT of the first fraction compared to the planning CT. Several parameters were extracted from the gamma analysis (e.g., average gamma value, standard deviation, percent above 1). These parameters formed patient-specific time series. Data from the first 24 patients were used as a training set for the HMM. The trained HMM was then applied to the remaining 28 patients and compared to manual clinical evaluation and fixed thresholds. RESULTS A three-category system was used for patient classification ranging from minor deviations (category 1) to severe deviations (category 3) from the treatment plan. Patient classified using the HMM lead to the same result as the classification made by a human expert 83% of the time. The HMM overestimate the category 10% of the time and underestimate 7% of the time. Both methods never disagree by more than one category. In addition, the information provided by the HMM is richer than the simple threshold-based approach. HMM provides information on the likelihood that a patient will improve or deteriorate as well as the expected time the patient will remain in that state. CONCLUSION We showed a method to classify patients during the course of radiotherapy based on relative changes in EPID images and a hidden Markov model. Information obtained through this automated classification can complement the clinical information collected during treatment and help identify patients in need of a plan adaptation.
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Affiliation(s)
- Nicolas Varfalvy
- Département de Radio-oncologie, CHU de Québec, 11 Côte du Palais, Québec, QC, Canada
| | - Ophelie Piron
- Département de Radio-oncologie, CHU de Québec, 11 Côte du Palais, Québec, QC, Canada.,Physics Department, Université Laval, Québec City, QC, Canada
| | - Marc François Cyr
- Département de Radio-oncologie, Centre Intégré de santé et de services sociaux du Bas-Saint-Laurent, 150, avenue Rouleau, Rimouski, QC, Canada
| | - Anne Dagnault
- Département de Radio-oncologie, CHU de Québec, 11 Côte du Palais, Québec, QC, Canada
| | - Louis Archambault
- Département de Radio-oncologie, CHU de Québec, 11 Côte du Palais, Québec, QC, Canada.,Physics Department, Université Laval, Québec City, QC, Canada
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